Chair back



FIG. 1 is a perspective view of the chair back from a first point of view.

FIG. 2 is a perspective view of the chair back from a second point of view.

FIG. 3 is a front view of the chair back.

FIG. 4 is a left side view of the chair back.

FIG. 5 is a back view of the chair back.

FIG. 6 is a right side view of the chair back.

FIG. 7 is a top view of the chair back; and,

FIG. 8 is a bottom view of the chair back.

The broken line showing is included for the purpose of illustrating unclaimed subject matter and forms no part of the claimed design. 

CLAIM The ornamental design for a chair back, as shown and described. 